Aircraft engine mounting



Jan.-30, 1945. wfs. FLETCHER 2,368,533

AIRCRAFT ENGINE MOUNTING I Filed April 14, 1943 INVENTOR. Wendell S. Fleicher BY g "Ur/QM ATTY.

' movements therebetween.

Patented Jan. 30; 1945 ED STATES,

AIRGRAFTENGINE MOUNTING Wendell s; Fletcher; 4 Sond eim; calm, as signer. to=Fletcher= Aviationfiorppration, Pasa dena, Calif I l ApplicationApril l, 1943i.serianNmm-woo This inventionrelates toresilient engine mountings fo1-=aircrat engines; particularly the radial aii'cooled type which are customarily at tached. to a= circular mounting ring a supported in spaced relationship -to a* firewall bulkheadi 'Cus' V tomarily; such amounting ring is builtinto the airplane or detachable as a unit--therefrom, and various engines "are more or; less. interchange ably =m0untedto'the ring ;-by a: plurality of shock absorbing -01" vibration dampening mountings.

High powered enginesare -=usually" so mounted that theconvergent mounting axes intersect the enginecenterr-lin'e near the center ofgravity of" the engine; but medium,.ppwered engines- (10 notrequire such complicated: and expensive mountings because-the power impulses are" of" lessermag-nitude in comparison with'theweight and? inertiaof the-- engine; In such-- engines it? has been heretofore proposed to-use spoollike'.

mounting-clamped to themountingring engine torque being carried: through the spool mounts against collars'or bracketswelded thereto; 'Ihe" difiiculty and expense of welding properly spaced: collars" on' the mounting ring have" heretofore been a handicaptothe-useofsuch spool mounts;

since theenginetorque should be evenly 1 disa tributed over-theusual -5, I 7" or 9 brackets" to pro;-

vent concentrationandroverloading offone bracki-v et accompanied by a corresponding restriction of the=resiliency-and vibrationabsorbing capacity 3 of the engine mount as a whole. I

It isaccordingly anobjectof this; invention.

to provide an improved and-'simplifiedsplit spool typeof rubberinsulated 'enginemounting; bracket which I is' individually pinned-- to the a mounting ring which being completely isolatedtherefrom j by" asynthetic rubber bushing clamped thereto under-slightpositive-pressure. Itisra furtherobject ofthis-inventionjto provide asymmetrical splitspool type, ofjengine,

mount bracketwherein each half has a metal; half I sleeve 'formeditoembrace the mounting ring, ashear pin being; mounted. therethrough and, held in place in, the sleeve and the outer shell ofthe-mounting'bracket; I It-is, also an object of this inventiontoprorvide' an engine mounting of the type described .I wherein the split halves ,of the mounting. brackets are" given 'axself' adjusting, movement about a,

singleoffset mounting boa orvstudfattachingjhe.

mounting bracket to the engine; whilethe relf siliency. of, the rubber; like: bond between the sleeves and'shells of the bracket allows appreciable relative twisting and axial and lateral Otherand further objects {off this; invention will become apparent as 'the' description" of the operation ot the mountingbrackets'proceeds in: I

connection with the accompanying; drawing which forms a part-0Pthis'specification and' in" which-: v I

Figure I is -afragmentary'elveation of air.-

plane engine and its-- mounting, ring" with the;

mounting bracket of this invention shown'thereparts-broken away -t omore cl-earlyjshow the dea viceofthis-inventionz I Figure III is an enlargedview of the mounting bracket.

Figure IV is a-central section'of the bracket v taken on theline liv- -Iv'of Figure-Ifli "ASSh OWIIOITthE drawing;

Anengine is-- indicated. generally by the, nu:- meral Ill and the crankcasejthereoff, by the numeral H. A rear cover, l2: for the crankcase usuallyr-carries' a; number. of? accessory drives.-, which have; beenomitted; herein; for 'clearness A; numberiofj peripherally outstanding; lugs I3 are; provided. around I the; crankcase, II and its-- cover I 2',which1lugs areboredto :recei-ve zamn unt ma bolt, 1 tud" I4 which, holds-3 a; pair-r f: th

, mounting.brackets toqbe described to;thercrankr-= aseand. iuaslccxver-u The en ine is supnolttedlfrom z. a. mounting-ring; I 5; by aanumberpi:suchimounts j ing bracketsr,thez in I 5 being;rigidlyvsl ppor.teda

fromttheairplanestructurebyist utsa "l vlikaohamountin s bracketz; is glformed-l of identical I halves; comprising; ribbedxshells a I 63 having a single-lboltzholeeII;attoneisideitorreceivezthemountLL ing bQltll on: stud IM and, a: pair? of smaller boltholes 'I 81 and: bolts": I 9 atits other or outer side relative -ttoz the i engine-axis.- The two halt shells-- are roughly bored. or" castte a diameter apprefciablyslarger the= diameter of the mounting synthetiorubbeniilflor otheroilfresiStantrubber like material. Subsequent references; to" rubber 5 will therefore be understood to 'include" synthetic varieties thereof? The rubber bushing, turn is-lined with= a thin, metal ilialfjshell ,2] conform,-

ing; to the; curvejof; the mounting ring I I 5;, The, n shell", 2 I; has. a, largeheadedj dowel, pin, 22, inserted,in,at,central-.hole therein andgprojecting inwardly, toenter, a -suitable .hole,.in the; mounting ring IvSZ-M g Each half shell, I6 rubbe17 bushing, and T inner:

shell'are bonded'together by vulcanizing therub- V ber like material to the shell and sleeve, the

Eigureqlfis a rear-elevtion ofrFigureI'with,

rubber in turn holding the dowell pin in its extended position in the inner sleeve.

With a series of these mounting brackets assembled between the engine and the mounting ring IS, the dead weight of the engine will have an individualized efl'ect on each of the mountings, ranging through tension at the top mounting, to twisting effects on the side mountings, and compression at the bottom mountings. The single off-set bolt or stud l4 allows each pair of half shells to adjust themselves. to the load and to cock slightly on the ring I 5 if the load so requires.

When the engine is in operation other and different loads are superimposed on the mounting brackets, among which may be noted the propeller thrust, torque reactions, power pulsations and other shocks and vibrations inherent in aircraft engines. The eccentric mounting of the shells to the crankcase, together with the resiliency of the rubber bonding the shells and sleeves together allows the several mounts to equally distribute the loads and to absorb or prevent the transmission of vibration to the mounting ring and then to the aircraft structure.

It will thus be seen that I have invented an improved and simplified vibration dampening engine mounting of the split spool type wherein the various loads and vibrations are evenly distributed among the several mounts to the end 1 that no one mounting will be overloaded and hence tend to be less efiicient as a vibration insulator even if not overloaded to the point of failure.

I am aware that various changes and modifications may be made in the disclosed embodiment of my invention without departing from the spirit or scope thereof. The invention is therefore to be limited only as indicated by the scope of the appended claims.

I claim as my invention:

1. In a radial aircraft engine mounting a circular mounting ring fixed relative to the aircraft, an aircraft engine having a substantially circular rear crankcase flange and cover of smaller diameter than said mounting ring, said crankcase flange and cover having spaced peripheral bosses apertured to receive mounting bolts therein, split mounting shells so constructed and arranged as to embrace said circular mounting ring and having offset apertures therein in, alignment with the apertured bosses on the crankcase cover, a bolt extending through said aperture into the apertured crankcase flange and cover for securing the shells thereto, split sleeves in said shells for engaging said mounting ring in annular spaced relationship to said shells, dowel pins disposed in said sleeves extending inwardly therefrom and adapted to engage in suitable apertures provided therefor in said mounting ring, and split rubber bushings interposed between said shells and said sleeves and bonded therebetween whereby to resiliently clamp said sleeves to said mounting ring.

upon clamping said shells together and to said crankcase flange and cover.

2. In a radial aircraft engine mounting a circular mounting ring fixed relative to the aircraft, an aircraft engine having a substantially circular rear crankcase flange and cover of smaller diameter than said mounting ring, said crankcase flange and cover having spaced peripheral bosses apertured to receive mounting bolts therein, split mounting shells so constructed and arranged as to embrace said circular mounting ring and having offset apertures therein in alignment with the apertured bosses on the crankcase cover, a bolt extending through said aperture into the apertured crankcase flange and cover for securing the shells thereto, split sleeves in said shells for engaging said mounting ring in annularspaced relationship to said shells, dowel pins disposed in said sleeves extending inwardly therefrom and adapted to engage in suitable apertures provided therefor in said mounting ring, said dowel pins having enlarged heads, and split rubber bushings interposed between said shells and said sleeves and bonded therebetween whereby to resiliently clamp said sleeves to said mounting ring upon clamping said shells together and to said crankcase flange and cover, and to hold the enlarged ends of the dowel pins against the sleeves.

3. A mount for connecting an engine to an engine supporting ring, said mount comprising symmetrical halves parted in the central plane of the supporting ring and axially cored in spaced relation to the ring, said halves being provided with at least two laterally extending apertured ears, a bolt extending through one pair of said ears and adapted to fasten the halves together on one side of the ring and to the engine, at least one bolt extending through a, pair of ears on the opposite side of the mount ii: that of the first mentioned bolt and adapted to clamp the halves about said supporting ring, half sleeves engaging said supporting ring within said mount halves, dowel pins adapted to anchor said half sleeves to said supportin ring, and rubber half bushings each bonded between one half sleeve and one half mount whereby each half sleeve, half bushing and half mount are bonded together into a unit.

4. A mount for connecting an engine to a supporting ring disposed in a plane at right angles to the engine axis, comprising a series of matched half shells axially cored for clearance about said ring, said shells having apertured ears projecting respectively inside and outside the plane of the ring, one pair of said ears being adapted to be bolted to said engine and to permit rocking of said matched shells about said bolt, resilient half bushings bonded in said half shells, half sleeves formed to embrace said ring and bonded to said resilient half bushings, and dowel pins projecting inwardly from said half sleeves and adapted to en age in suitable apertures provided therefor in said ring.

5. In combination with a mount for a radial in ternal combustion engine including a mounting ring, means for resiliently sup-porting the engine from said ring comprising interchangeable halfshells adapted to embrace said mounting ring, means for simultaneously clamping said halfshells together and to the engine comprising a bolt or stud passing through suitable apertures in said half-shells on one side of said mounting ring and secured to said engine whereby said halfshells are pivotally attached to the engine for selfalignment with said mounting ring, and means for resiliently engaging said half -shells to said mounting ring comprising inner half sleeves in spaced alignment with the half-shells and having shear engagement with said mounting means, and rubber half bushings bonded between said inner half sleeves and said half-shells, said rubber bushings being adapted to transmit combinations of compression and shear loads between the sleeves and the shells.

WENDELL S. FLETCHER. 

